A micro-rotor, also known as a micro-rotor movement, is a type of automatic watch movement where the oscillating weight, or rotor, is smaller and integrated into the movement itself rather than being mounted on top of it. This design allows for a thinner watch profile, as the micro-rotor is embedded within the plane of the movement, rather than adding height to the watch. The micro-rotor is typically off-centered and can be made from dense materials like gold or platinum to ensure efficient winding of the mainspring despite its reduced size.

The innovation of the micro-rotor allows watchmakers to create automatic watches that maintain the elegance and slimness of manual-wind watches, appealing to those who prefer a more streamlined aesthetic. This design requires precise engineering and craftsmanship, as the smaller rotor must still provide sufficient energy to wind the watch effectively. Micro-rotor movements are often found in high-end and luxury watches, where the emphasis is on both technical sophistication and aesthetic refinement. The use of a micro-rotor can also allow for a more open view of the movement through the case back, enhancing the visual appeal and showcasing the intricate mechanics of the watch.